<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .static {
            width: 100px;
            height: 100px;
            background-color: #f66;
            z-index: 109;
        }
        .relative {
            width: 200px;
            height: 50px;
            left: 10px;
            top: 10px;
            background-color: red;
            position: relative;
        }
        .absolute {
            position: absolute;
            left: 0;
            top: 0;
            width: 50px;
            height: 100px;
            background-color: #000;
        }
        .fixed {
            position: fixed;
            left: 10px;
            right: 10px;
            top: 0;
            bottom: 0;
            width: 100%;
            height: 100px;
            border: 1px solid #000;
            margin: 10px;
            padding: 10px;
            background-color: green;
        }
    </style>
</head>
<body>
    <div class="static"></div>
    <div class="relative"></div>
    <span>9999</span>
    <div class="absolute">
        <!-- <div class="child" style="position: absolute;width: 100%;height: 100%;"></div> -->
    </div>
    <!-- <div class="fixed"></div> -->
</body>
</html>